Oven.



R. W. DAVENPORT.

OVEN..

APPLICATION rum Nov. z5, 1912.

1, 108,890. Patented Sept. 1, 1914.

7155-671 esseg UNITED STATES PATENT OFFICE.

RANSOM W. DAVENPORT, F DETROIT, MICHIGAN, ASSIGNOB TO DETROIT STOVEWORKS, OF DETROIT, MICHIGAN, A CORPORATION OF MICHIGAN.

ovnN.

Specification of Letters Patent.

`Patented Sept. 1, 1914.

Application filed November 25, 1912. Serial No. 733518.- I

America, residing at Detroit, in the county of XVayne and State ofMichigan, have invented certain new and useful Improve-1 ments in Ovens7of which the following is a specilicatiom reference being `had thereinto the accompanying drawings.

v The invention relates to ovens, being more particularly designed foruse in connection with electric heaters.

It is the object of the invention; first, to obtain an effective heatinsulation; further to utilize the heat generated in one oven chambereither for heating .the same or an adjacent oven 7chamber; and stillfurther to obtain a convenient and effective arrangement of vthe heatingelements.

vWith these objects in view, the invention consists in the constructionas hereinafter set forth.

In the drawings: Fig. 1 is a perspective View of the oven, pratly brokenaway; Fig. 2 is a cross section; Fig. 3 is an enlarged section showingthe arrangement of the heat-reflecting and nonconducting elements of theheat insulation; Fig. l is a view similar to Fig. 3 showing a modifiedconstruction ;y Fig. 5 is aperspective view of the lamp and its fitting;and Fig. 6 is a vcross sectionthrough one of the heating units.

A is theoven casing, which preferablyk in.- closes two supcrposed ovenchambersB and C the un ier chamber constituting a bakin 7 .t I D g oven7and thc lower chamber a broiling oven. D and D are electrical heatingunits arranged respectively at the top of the chambers B and C, and in aposition to radiate:

their heat downward.

E are doors at the front of the oven chambers B and C.

To make the most ellective use ofthe heat generatedy inthe units D andD,` the construction of the walls of the oven chamber' is such as toform an effective heat insulation. This` I preferably secure bycombining alternate reflecting and non-conducting layers as, follows: Fis an inner layer or lining of the oven, which is formed of some goodheatconductin material-such as sheet aluminum. Adjacent to this liningis a non-con-V ductingl layer. formed in any suitable way, as;

'wit-h, is

by the a for instance, by a cellular `body G whichvl preventscirculatlon'of the air. Beyond this .non-conducting medi'umis anotherbright heat-reflecting surface I' andy then anotherl non-,conductingmedium G and another heat-reflecting surface'l. This alternation ofreflecting and non-conductin layers may continue. to any extent desire)the outer case J being formed of any suitable material ihaving theproper strength and. rigidity.

This construction insures partial reflectionl of the 'incident radiatinghea-t at the surface F, while that portion of theradiated heatabscrbedby the relector,'-together with the heat derived from the airincontact theredprevented from .rapid dissipation )acent non-conductingmedlum'G, This non-conducting medium will cause av drop in temperaturebetween its `faces S0` that the second heat-reiecting surface I will oeat a lower. temperature than the-first surface F. lVith each succeedingalternate reflecting surface and heat-insulation .there will be a dropin temperature so that a very` ell'ective heat-insulation is obtained.Where, the oven is used for ordinary cooking oper-Y ations thetemperature within thechamher will never rise to the point which willmelt or destroy the aluminum sheets, and therefore this material, whichhas the property of. retaining a bright surface even when heated to aconsiderable extent, best adapted for the inner lining; andf the outerreflecting Surface I, being always at' a. relatively low y temperature,canbe made. of' tin or other bright metal whichmwculdbe discolored ifsubjected to .the inner-oven tempera-ture.

c On the other hand Where the oven is `used for operations requiring ,aA.higher tempera- "ture which would .be destructive Ato the aluminum(plate-s,l as well asl` to all other ava ilahle bright surfaces, I formthe -inner lining -0f K, or other suitable material, and place` anon-conducting layer L immediately adjacent thereto, beyond which is thebright heat-reflecting surface F; as shown.

in Fig. 4.. The principle employed in both constructionshown Figs. 3 and4., is to, placejthe: heatelepting surface as near the.

sourceof heater inner lining of the oveli chamber as is said surface. ,i

-The'heating units 'D and ,DT are prenten: ebhc constructed .se to,produrerect heat Without destroying radiation into the oven chamber fromas large a portion of the resistor as possible. To secure this effectthe heat resistor M is preferably in theform of a coil wound upon anelectrical insulating` core M, lwhich eX- tends horizontally adjacent tothe top wall of the oven chamber, and this core is preferablysubstantially triangular in cross section, with the apex downward. Byreason of this shape two-thirds of the resistor M will be arranged atangles permitting of direct downward radiation of the heat, while onlyone-third passes above the core and radiates heat upward. rl`he heatradiating upward is reflected downward again `by the bright lining F,but there is Aa loss due to the imperfection in tlie reflector, which isavoided in the portions of the resistor radiating directly downward.

In the lower oven chamber C, constituting the broiling oven, a reflectorN, preferably of aluminum plate, is arranged above the heating unit D,to reflect downward any upward radiation from said heater. Thisreflector N does not, however, form a perma nent portion of thepartition between the ovens B and C, but said partition is formed Vby aplate O of dark metal-such as ironwhich is a poor reflector and a goodheat radiator. iIhus whenever it is desired to use the heater D forheating the bottom of the oven B, the reflector N is removed from itsposition between said heater and partition O, and is placed below theheater D, as indicated by the dotted line N Fig. S2. This will reflectthe downward radiation from the heater D upward, and as the partition Ois of metal having dark Aabsorbing' surface, being. both a good heatradiator and heat conductor, the upwardly directed heat radiation willpass easily into the chamber B.

As electrical heating units are destructible it is desirable to mountthe same so that they may be conveniently removed and replaced. This Iaccomplish by forming in the side wall of the oven casing a channel P,in which the electrical conductors 13 for connection with the heatingunits are placed, and which also contain insulator blocks Q containingthe terminal contacts. The heating units, including the core member Mand the resistor M wound thereon, are insertible through apertures Q inthe blocks Q, and the outer ends of said units are provided withterminal contacts It for engaging with the corresponding contacts on theblocks Q, thereby completing thel connection of the'unit with theelectric circuit. The contacts R are preferably mounted upon a vheadmember M2 of the core member M, and are-insertible in sockets QZ in theblocks Q,

thereby effecting not only the electrical 'connection but also amechanical coupling. The rods M2 as well as the blocks Q, lie within the'recess P, and when 'the parts'are'in posi incasso tion a cover plate P2is secured to the oven casing to close the recess P. Thus at any 'timewhen the resistor of one ofthe units is burned out, it may be removedand replaced without skill or electrical knowledge on the part of theoperator. A series' of blocks Q is arranged in the channel P, and inaddition to those which are employed as the heating units one or more ofthese blocks may be used for the connection of an electric light-such asS, Fig. 5-the bulb of which passesthrough this aperture Q andilluminates the interior of the oven.

In operation, the electric circuits for the heating units are controlledby suitable switches, not shown, and may be used for heating either orboth of the oven chambers B and C as desired,

`What I claim as my invention is:

l. In anoven, a casing divided into a plurality of chambers, suitableheaters ar: ranged therein,a heat reflecting shield adjustable topositions upon opposite sides of one of said heaters, a heat insulatingwall, comprising a bright, metallic heat reflecting plate, positioned insaid wall at the nearest point to the inner surface which is at.atemperature below that which is destructive to the bright surface, and aheat non-conducting layer adjacent to the said heat refleeting plate. ql

In an oven, a casing divided into adjacent separate chambers, a heatinsulating wall. comprising a bright metallic heat reflecting liningformed of material non-corrodible at the oven temperature, an adjacentlayer of heat non-conducting material, an outer reflecting metallicplate of a material corrodible at the temperature of the 'wall in theposition `in which it is located, and a plurality 'of recesses arrangedin one of the walls of said oven and adapted to 4 receive-suitableheating' units.

3; Inj an oven, a casing divided into a plurality of oven chambers, aheater in one of said chambers adjacent to the partition between thesame and the other chamber, and means for directing the heat of saidheater alternatively into the chamber'in which it is located and intothe adjacent chamber.

4:. In an oven, the combination with a casing, divided into adjacentseparated chambers, of an electrical heater in one of said chambersadjacent to the partition between Athe same and the otherlchamber, andan imperforate partition between said chambers, adjustable to vary thepenetration of heat therethrough.

5. In an oven, the combination with a casi ing, divided into adjacentoven chambers, of an electrical heater in one of said chambers adjacentto the separating partition,

of good heat-absorbing and radiating `fnaterial, and aheatreecting`shield remor-l an imperforate partition having a surfaceably placed between said heater and partition.

6. In an oven, the combination with a casing divided into adjacent ovenchambers, of lan imperforate partition between said chambers formed of agood heat-penetrating material, an electric heater in one of saidchambers adjacent to said partition, and a heat-reiiecting shieldadjustable to positions upon opposite sides of said heater.

7. The combination 'with an oven having a recess in the Wall thereof, ofxed electrical terminal contacts located in said recess, and anelectrical heating unit insertible through an aperture in said recessinto the oven casing,` and having cooperating con tacts for engagingwith said fixed contacts.

-8. The combination with an oven casing having a channeled Wall, ofelectrical conductors located in the channel of said Wall, a series ofterminal contacts connected to 4said conductors and also located in saidchannel7 a plurality of electrical 'heating units insertible throughapertures in said channel into the oven chamber, contacts on said unitsior coperating with the fixed contacts in said channel, .t rernnra; iecover for sald channel.

a heat insulating Wall, oompriain a bright metallic heat reflecting.lining perature, an adjacent layer of heat nonconducting material, andan outer reecting metallic plateof a material corrodble at thetemperature of the wall in the position in which it is located.

10. ln an' oven, heating units arranged therein, a heat insulatin wall,comprising a bright, metallic heat-re ecting plate; p`ositioned in saidWall at the nearest point t0 the inner surface which is at'a'temperature below that which is destructiveuto the bright surface7 and aheat non-conducting layer adjacent to said heat-reilectin plate.'

` In testimony whereof I a my signature in presence of two witnesses.

RANSOM W. DAVENPORT.

Witnesses:

JAMES P. BARRY, ADnLAmn I. ADAMS.

' Uopies o! this potent :any be obtained for ivo conta non, by honingthe Commissioner of Patents,

, Wallington, D. 0.

9. In an oven, heaters arranged therein,v

o rmed of material non-corrodible at the oven ternv

